Quality of life in the patients with central diabetes insipidus assessed by Nagasaki Diabetes Insipidus Questionnaire

Central diabetes insipidus (CDI) is characterized by polyuria and polydipsia due to a deficiency of vasopressin. Currently, the treatment goal for CDI is improvement of quality of life (QOL) by desmopressin (DDAVP) without developing hyponatremia. However, there is no reliable measure for QOL in CDI patients. We evaluate our original questionnaire for QOL, consisting of 12 questions focusing on polyuria, polydipsia, and DDAVP treatment, in CDI patients who underwent a switch from nasal spray to oral disintegrating tablets of DDAVP. Twenty-five CDI patients under nasal DDAVP treatment, six with newly developed CDI, and 18 healthy individuals without known polyuric/polydipsic disorders as control subjects were enrolled. QOL scores were determined by our questionnaire at the enrollment and 3 months after the start of oral DDAVP treatment and were examined by the Wilcoxon signed-rank test. Eleven questions detected improvement in QOL. The sum of the QOL scores of the eleven questions increased from 29.2 +/- 5.6 under nasal to 36.8 +/- 4.5 under oral DDAVP (p < 0.001). There were no clinically relevant changes in serum levels of Na. After eliminating two questions about DDAVP treatment, the sum of QOL scores was 15.3 +/- 6.5 in untreated CDI patients, 24.4 +/- 5.2 in those with nasal treatment, 28.9 +/- 4.9 in those with oral DDAVP, and 29.5 +/- 3.6 in healthy controls. The difference among groups was significant (p < 0.05 in Steel-Dwass test) except between patients treated with oral DDAVP and healthy controls. Our questionnaire can be used to accurately assess QOL in CDI patients.